Method for Rendering Outline of Polygon and Apparatus of Rendering Outline of Polygon

摘要

A database compiler sequentially selects element points constituting an outline of a polygon corresponding to polygon data obtained from a map database. When it is determined that one of the selected polygon element points is positioned on one of map mesh boundaries, a coordinate of the polygon element point is shifted toward an inside of the polygon by 1. In a map display process, when the polygon is to be emphatically displayed, the polygon data which has been subjected to the coordinate shifting process is obtained. When it is determined that a portion of the outline of the polygon corresponding to the obtained polygon data is positioned on one of the map mesh boundaries, the portion of the outline is not emphatically displayed and the other portions of the outline are emphatically displayed.